Newtons Laws - Angular momentum Flashcards
What is angular motion?
Movement around a fixed point or axis
When does angular motion occur?
When a force is applied outside the centre of mass
What is an off centre force called?
An eccentric force
What is torque?
Torque is a rotational force which causes the body to rotate around an axis
What is newton’s first law of angular motion?
Law of inertia
- A rotating object will continue in its state of angular momentum until an external rotational force (torque) is applied to it
What is an example of Newton’s first law of angular motion?
An ice skater will continue to rotate in the air until they land. Here the ground exerts an external force (torque) which changes their state of angular momentum. A decrease in angular velocity around their longitudinal axis
What is Newton’s second law of angular motion?
Law of acceleration
- The rate of change of angular momentum of an object is directly proportional to the rotational force (torque) acting on it
What is an example of Newton’s second law of angular motion?
The faster a diver throws their head and arms forwards off a diving board, the greater their angular velocity will be around their transversal axis
What is Newton’s third law of angular motion?
Law of action/reaction
- For every rotational force applied there is an equal and opposite rotational force exerted
What is an example of Newton’s third law of angular motion?
When a diver throws their arms and head forwards and down, their legs will want to go backwards and up. This happens around the transversal axis
What is angular displacement?
The smallest change in angle between the start and finish point
What is angular displacement measured in?
Radians
What does 1 radian equal in degrees?
57.3 degrees
What is angular velocity?
The rotational speed of an object around the axis it is rotating
What is angular acceleration?
The rate of change of angular velocity
What is the equation for angular velocity?
Angular velocity = angular displacement (rad) / time taken (s)
What is the equation for angular acceleration?
Angular acceleration = change in angular velocity (rad/s) / time taken (s)
